package ticket

import (
	"strings"
	"unicode"
)

// BoardList is a project-scoped view/filter over tickets by status.
type BoardList string

const (
	BoardAll        BoardList = "all"
	BoardBacklog    BoardList = "backlog"
	BoardInProgress BoardList = "in_progress"
	BoardDone       BoardList = "done"
)

// AllBoardLists is the ordered picker list.
var AllBoardLists = []BoardList{BoardAll, BoardBacklog, BoardInProgress, BoardDone}

// Label returns a display name for the board list.
func (b BoardList) Label() string {
	switch b {
	case BoardAll:
		return "All"
	case BoardBacklog:
		return "Backlog"
	case BoardInProgress:
		return "In Progress"
	case BoardDone:
		return "Done"
	default:
		return string(b)
	}
}

// Shortcut returns the board-menu hotkey (first letter of the label).
func (b BoardList) Shortcut() rune {
	label := b.Label()
	if label == "" {
		return 0
	}
	return unicode.ToLower([]rune(label)[0])
}

// Index returns the position in AllBoardLists.
func (b BoardList) Index() int {
	for i, bl := range AllBoardLists {
		if bl == b {
			return i
		}
	}
	return 0
}

// ParseBoardList validates a board list id; invalid values become BoardAll.
func ParseBoardList(s string) BoardList {
	b := BoardList(s)
	switch b {
	case BoardAll, BoardBacklog, BoardInProgress, BoardDone:
		return b
	default:
		return BoardAll
	}
}

// BoardFilter is a multi-select set of board lists (OR semantics).
type BoardFilter []BoardList

// ParseBoardLists parses a comma-separated list id string (legacy single values work).
func ParseBoardLists(s string) BoardFilter {
	s = strings.TrimSpace(s)
	if s == "" {
		return BoardFilter{BoardAll}
	}
	parts := strings.Split(s, ",")
	var out BoardFilter
	seen := map[BoardList]bool{}
	for _, p := range parts {
		bl := ParseBoardList(strings.TrimSpace(p))
		if seen[bl] {
			continue
		}
		seen[bl] = true
		out = append(out, bl)
	}
	return NormalizeFilter(out)
}

// FormatBoardLists serializes a filter for config persistence.
func FormatBoardLists(f BoardFilter) string {
	f = NormalizeFilter(f)
	parts := make([]string, len(f))
	for i, bl := range f {
		parts[i] = string(bl)
	}
	return strings.Join(parts, ",")
}

// NormalizeFilter ensures a non-empty filter; All alone if empty or only All.
// If All is combined with others, All is dropped.
func NormalizeFilter(f BoardFilter) BoardFilter {
	if len(f) == 0 {
		return BoardFilter{BoardAll}
	}
	hasAll := false
	var others BoardFilter
	seen := map[BoardList]bool{}
	for _, bl := range f {
		if bl == BoardAll {
			hasAll = true
			continue
		}
		if seen[bl] {
			continue
		}
		seen[bl] = true
		others = append(others, bl)
	}
	if len(others) > 0 {
		return others
	}
	if hasAll {
		return BoardFilter{BoardAll}
	}
	return BoardFilter{BoardAll}
}

// Contains reports whether bl is in the filter.
func (f BoardFilter) Contains(bl BoardList) bool {
	for _, x := range f {
		if x == bl {
			return true
		}
	}
	return false
}

// Label returns a short header label for the active filter.
func (f BoardFilter) Label() string {
	f = NormalizeFilter(f)
	if len(f) == 1 {
		return f[0].Label()
	}
	parts := make([]string, len(f))
	for i, bl := range f {
		parts[i] = bl.Label()
	}
	return strings.Join(parts, "+")
}

// Matches reports whether a ticket status is visible under this filter.
func (f BoardFilter) Matches(status Status) bool {
	f = NormalizeFilter(f)
	if f.Contains(BoardAll) {
		return true
	}
	for _, bl := range f {
		if bl.Matches(status) {
			return true
		}
	}
	return false
}

// DefaultStatus is used when creating a ticket under this filter.
func (f BoardFilter) DefaultStatus() Status {
	f = NormalizeFilter(f)
	if len(f) == 1 {
		return f[0].DefaultStatus()
	}
	return StatusTodo
}

// Matches reports whether a ticket belongs on this board list.
func (b BoardList) Matches(status Status) bool {
	switch b {
	case BoardAll:
		return true
	case BoardBacklog:
		return status == StatusTodo
	case BoardInProgress:
		return status == StatusInProgress
	case BoardDone:
		return status == StatusDone
	default:
		return true
	}
}

// DefaultStatus is the status used when creating a ticket on this list.
func (b BoardList) DefaultStatus() Status {
	switch b {
	case BoardInProgress:
		return StatusInProgress
	case BoardDone:
		return StatusDone
	default:
		return StatusTodo
	}
}